1. Field of the Invention
The present invention relates to a steering wheel provided with a shock absorber, and more specifically to a steering wheel provided with uniform shock absorbing characteristics irrespective of points and directions at and in which a shock is applied.
2. Description of the Prior Art
FIGS. 1A and lB show a prior-art steering wheel provided with a shock absorber by way of example, which is disclosed in Japanese Published Unexamined (Kokai) Utility Model Application No. 61-103276. This prior-art steering wheel 1 comprises a hub 2 attached to a steering shaft 3, at least one spoke 4 extending from the hub 2, a rim 5 supported by the spoke 4, and a cover pad 6 attached to the upper surface of the hub 2, as shown in FIG. 1A. Further, as shown in FIG. 1B, a shock absorber is provided between the hub 2 and the cover pad 6, which comprises a lower (hub side) plate 8 formed with a rectangular opening 8a and attached to the upper surface of the hub 2, an upper (cover side) plate 10 formed with a rectangular opening 10a and attached to the lower surface of the cover pad 6, and a cylindrical hollow shock absorbing member 11 (made of metal or hard rubber, for instance) sandwiched between the two plates 8 and 10 by partially fitting the outer circumferential surface of the cylindrical shock absorbing member 11 to the two rectangular openings 8a and 10a, respectively.
In this prior-art steering wheel 1, when a shock is applied to the cover pad 6, since the shock absorbing member 11 is deformed or crushed between the two plates 8 and 10, it is possible to absorb a shock energy applied to the cover pad 6.
In this prior-art steering wheel provided with a shock absorber, however, there exists a problem in that it is impossible to absorb a shock applied to the rim 5 by the deformation or the crush of the shock absorbing member 11. Therefore, in the prior-art steering wheel as shown in FIGS. 1A and 1B, it has been necessary to provide another shock absorbing member between the hub 2 and the spoke 4, thus resulting in another problem in that the number of parts is large and therefore the assembly steps and the manufacturing cost also increase.
Further, in the prior-art steering wheel as shown in FIGS. 1A and 1B, since the shock absorbing member 11 is supported by the two upper and lower plates 10 and 8 in such a way that the outer circumferential surface of the absorbing member 11 is brought into contact with the rectangular opening 8a or 10a at four different corners or along the two longitudinal cutout lines and further the length of the opening 8a or 10a is relatively long, there exists a problem in that the shock absorbing characteristics or the rigidity of the shock absorbing member 11 is subjected to the influence of points and directions at and in which a shock is applied to the absorbing member 11. This is because the deformation or crush shapes of the absorbing member 11 are different according to points and directions at and in which a shock is applied. For instance, the shock absorbing member 11 is crushed at a corner, along the radial and/or axial direction or in the directions obliquely to the radial and/or axial direction according to various shocks applied to the cover pad 6 at various points and in different directions.
Further, in the prior-art steering wheel as shown in FIGS. 1A and 1B, since the shape of the shock absorbing member 11 is simply cylindrical, it has been difficult to obtain uniform shock absorbing characteristics irrespective of points and directions at and in which a shock is applied.